Morales followed his father’s footsteps into the boxing ring and turned pro in 1993. He won the NABF super bantamweight title before stopping Daniel Zaragoza (KO 11) for the WBC 122-pound title in 1997. “El Terrible” registered nine successful defenses including wins over Junior Jones (TKO 4), Wayne McCullough (W 12) and Marco Antonio Barrera (W 12). He became a two-division champion with a 12-round win over Guty Espadas Jr. (W 12) for the WBC featherweight title in 2001. He lost the title to Barrera (L 12) in 2002 but reclaimed the vacant laurel from Paulie Ayala (W 12) when Barrera refused the belt. He added a third divisional title in 2004 with a pair of 12-round decisions over Jesus Chavez for the WBC super featherweight strap and Carlos Hernandez for the IBF belt. Morales met his rival Barrera in a rubber match (L 12) before defeating Manny Pacquiao in 2005 (W 12). He met Pacquiao twice more in 2006 (TKO by 10, KO by 3). In 2011 he defeated Pablo Cano for the WBC light welterweight title to become the first Mexican boxer to win titles in four weight divisions. After back-to-back losses to Danny Garcia (L 12, KO by 4), Morales retired in 2012 with a pro ledger of 52-9 (36 KOs).